Bicycle stem



FIG. 1 is a perspective view of a bicycle stem, showing my new design in which the front end and tube are shown in broken lines which form no part of the claimed design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a side elevational view thereof, of which the opposite side is a mirror image;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is a top plan view thereof. 

The ornamental design for a bicycle stem, as shown and described. 